1. Field of the Invention
The present invention relates to an electrical socket, and particularly to a ZIF (Zero Insertion Force) mobile socket for use with a PGA (Pin Grid Array) chip.
2. Description of the Prior Art
A ZIF socket is often used to mount a PGA chip onto a printed circuit board (PCB). One example of such connectors comprises a plastic base, a plastic cover mounted onto the base, a plurality of electrical contacts received in the base, and a metallic cam actuator. The cover is actuated to slide on the base by rotation of the metallic cam actuator, thereby causing pins of the PGA package mounted on the cover to engage with/disengage from the contacts in the base. Referring to FIG. 6, the plastic cover 8 defines an arc-shaped recess 81 in one side thereof. A stop wall 82 is provided at each end of the arc-shaped recess 81. The metallic cam actuator 9 comprises an outwardly protruding protrusion 91. The protrusion 91 of the cam actuator 9 is rotatable in the arc-shaped recess 81. Rotation of the cam actuator 9 causes the cover 8 to slide on the base (not shown), mating or unmating the pins of the PGA package (not shown) on the cover 8 with the contacts (not shown) of the base.
However, when the protrusion 91 rotates between the two limit positions defined by the stop walls 82 and abuts against one of the stop walls 82, the large force exerted by the protrusion 91 may tend to damage the stop wall 82 during operation of the mobile socket, thereby causing malfunction of the socket. Further, the plastic cover 8 is apt to be worn out by the rotation of the metallic cam actuator 9 therein, resulting in a shortened life thereof, and in turn a shortened life of the mobile socket.
Therefore, an improved mobile socket is desired to overcome the disadvantages of the prior art.
The major object of the present invention is to provide a ZIF PGA socket having a protecting mechanism which protects the cover and the base of the mobile socket for a lengthened life.
An electrical mobile socket in accordance with the present invention comprises an insulative base, a dielectric cover, a plurality of electrical contacts, a metallic cam actuator, a protecting mechanism and a washer. The base comprises an insulative housing, an opening and a plurality of passageways. The insulative housing comprises a T-shaped recess in the middle of an end thereof. The bottom of the recess defines a through hole. The cover comprises an insulative housing, an opening and a ledge. The ledge has a top hole and a pair of stop walls. The protecting mechanism comprises a T-shaped metal cover plate insert molded in the cover and a T-shaped metal bottom plate received in the recess of the base. The cover plate defines an elongated slot and a pair of arc-shaped holes provided on opposite sides of the slot at the middle and in communication with the slot. The two arc-shaped holes together with a middle portion of the slot define a through hole. A pair of upwardly extending cam stoppers are provided on one side of the slot and on opposite sides of one arc-shaped hole. The bottom plate defines a rectangular through hole in the middle thereof. The cam actuator comprises an upper disk, a lower disk and a lower cam block. The upper disk has a lateral protrusion protruding from a side thereof. The cam block comprises a riveting end coaxial with the cam block at a lower end thereof. The rotational axis of the cam block is offset from a rotational axis of the lower disk. Rotation of the cam actuator causes the cover to slide on the base, mating or unmating pins of a PGA package on the cover with the contacts of the base.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description of the present embodiment when taken in conjunction with the accompanying drawings.